Cable splice closure

ABSTRACT

A cable splicing closure includes a base having ports for the entry of cables to be spliced, and a tubular cover for sliding axially over a peripheral surface of the base. The surface is formed with a groove which tapers towards the end from which the cover is applied and which carries an O-ring seal that is engaged by the cover and which rolls along the tapering surface of the groove as the cover is slid onto the base. The O-ring seal is rolled substantially more than 50 percent, but less than 100 percent, of its peripheral length when it is rolled into its final sealed position. Thus, the O-ring will exert a force in a direction urging the tubular cover more firmly onto the base.

BACKGROUND OF THE INVENTION

This invention relates to a cable splice closure, particularly forcommunications cables (including optical fibre cables).

Typically a closure for cable splices comprises a base having ports forthe entry of the cables, and a tubular cover which is closed at one endand arranged to fit at its other end around the periphery of the base,the cover when fitted enclosing splices which have been made between thecables. It is necessary to form a seal between the base and the end ofthe cover and typically a clamping arrangement is used.

SUMMARY OF THE INVENTION

We have now devised a cable splice closure which includes a simple buteffective seal between the cover and base.

In accordance with this invention there is provided a cable spliceclosure which comprises a base having ports for the entry of cables tobe spliced, and a tubular cover for sliding axially over a peripheralsurface of the base, said surface tapering towards the end from whichthe cover is applied and carrying an O-ring seal which is engaged by thecover and rolled along said tapering surface as the cover is slid ontothe base.

Thus, as the tubular cover is slid onto the base, the O-ring seal isrolled into a position where it is more firmly gripped between the coverand the base, and so seals effectively.

A quantity of sealing composition e.g. grease may be applied to thetapering surface. This may be applied either in the field immediatelybefore the cover is slid onto the base, or in the factory (in which caseit is provided with a temporary protection, e.g. a length of tape woundaround the base to cover the grease).

In one embodiment the tubular cover is closed at one end by an end wall.The end wall of the cover is preferably formed with a projection formounting the closure to a support rail.

In an alternative embodiment the tubular cover is open at its oppositeends, so that the cover may be applied to bases at its opposite ends.The bases may be interconnected so that the tubular cover can be appliedaxially from one end of the interconnected bases, each base thus has itsperipheral surface tapering towards the end from which the cover isapplied.

Also in accordance with this invention there is provided a base for acable splice closure, the base comprising ports for the entry of cablesto be spliced, and a peripheral surface over which a tubular covermember is to be axially slid, said surface tapering towards the end fromwhich the cover is to be applied and carrying an O-ring seal arranged tobe engaged by the cover and rolled along said tapering surface as thecover is slid onto the base.

Embodiments of this invention will now be described by way of examplesonly and with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an end view of an embodiment of cable splice closure inaccordance with this invention;

FIG. 2 is a longitudinal section through the cable splice closure, onthe line II--II shown in FIG. 1;

FIG. 3 is a longitudinal section through the cable splice closure, onthe line III--III shown in FIG. 1;

FIG. 4 comprises sectional views to illustrate diagrammatically themanner in which an O-ring of the closure is displaced as a tubular coveris slid onto the closure base; and

FIG. 5 is a sectional view through an alternative embodiment of cablesplice closure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. to 1 to 3 of the drawings, there is shown anembodiment of cable splice closure which comprises a base 10 and atubular cover 30, each of plastics material. The base 10 comprises atubular portion 12 and an end wall 14, with a plurality of tubularprojections e.g. 16 extending outwards from its end wall 14 and formingcable entry ports. The tubular portion 12 has a peripheral surface 18formed with a groove 20, an edge of the groove being formed by a ring 22applied to the end of the tubular portion 12 of the base. The peripheralsurface of the tubular portion 12, within the groove 20, tapers inwardlyin the axial direction towards the ring 22 and carries an O-ring 24. Thetubular cover 30 is closed at one end and its other end is dimensionedas a sliding fit over the outside of the tubular portion 12.

As shown in FIG. 4, as the tubular cover 30 is slid over the tubularportion 12 of the base, its inner surface engages the O-ring 24 andcauses the latter to roll along the tapering surface of the groove 20,from the smaller-diameter side to the larger-diameter side of thegroove. Thus, the O-ring 24 is compressed and therefore becomes morefirmly gripped between the inner surface of the cover 30 and the outerperiphery of the base 10, to form an effective seal. The rolling of theO-ring imparts a twisting action to it, and if at its final position theO-ring has been rolled substantially more than. 50% (say 75%) of itsperipheral length, then it has a natural tendency to roll the remainingamount forward to its original configuration: accordingly, the O-ring,in its final position, exerts a twisting force in a direction urging thetubular cover onto the base.

Catches may be provided to lock the cover onto the base: in the exampleshown, the cover has two longitudinally projecting flexible catches 33which snap engage over the end wall 14 of the base 10.

The groove 20 may be filled or partially filled with grease to improvethe seal. The grease may be applied in the field, immediately prior tosliding the cover 30 onto the base: alternatively the grease may beapplied in the factory, in which case it is preferably protected by alength of tape would around the base over the groove 20.

As shown, the outer end of the cover 30 may be formed with a projection32 defining a groove: this is for mounting the closure to a supportrail, but also a suitable tool can be engaged into the groove forpulling the cover from the base 10.

Referring to FIG. 5, there is shown an alternative embodiment of cablesplice closure which comprises two bases 50,51 mounted at opposite openends of a tubular cover 54. The bases 50,51 are interconnected by two ormore webs 52 which define openings 53 that allow access into the region56 between the two bases. The base 50 is similar in construction to thebase 10 shown in FIGS. 1-4, and like parts are given like referencenumerals. The cover 54 is stepped in diameter and an inwardly projectingannular flange 55 is formed at its reduced diameter end to seal againstthe base 51. The closure is sealed by inserting the interconnected bases50,51, into the cover 54 from its enlarged diameter end. The peripheralsurface of the grooves 20,58 in the two bases 50,51 both taper inwardlytowards the end from which the cover 54 is applied, so that theirrespective O-ring seals 24,59 are compressed against the inner surfaceof the cover 54 to form an effective seal at both ends.

In use, the closure shown in FIG. 5 may be connected in series with acable, so that interconnections may be made to the cable. The cover 54may be pulled back over the cable in order to gain access to theinterconnections inside the closure.

I claim:
 1. A cable splice closure for cables to be spliced,comprising:a) a first base member having ports receiving the cables tobe spliced, and a peripheral surface tapering toward an end of saidfirst base member: b) an O-ring adapted to be located in a finalposition on said tapered peripheral surface, and having a peripherallength; and c) a tubular cover means for sliding axially over saidtapered peripheral surface, for engaging said O-ring, and for rollingsaid O-ring along said tapered peripheral surface, wherein said cablesplice closure is arranged to permit said O-ring to be rolled by saidtubular cover means from a non-stressed orientation over said peripheralsurface by substantially more than 50%, but less than 100%, of saidperipheral length to said final position, such that said O-ring has anatural tendency to rotate forward to said non-stressed orientation, andsuch that said O-ring exerts a twisting force in a direction urging saidtubular cover means onto said first base member.
 2. A cable spliceclosure according to claim 1, further comprising: d) a quantity ofsealing composition applied to said tapering peripheral surface.
 3. Acable splice closure according to claim 1, further comprising:a secondbase members substantially similar to said first base member, whereinsaid tubular cover means is provided with two open opposite ends,arranged for sliding axially over respective peripheral surfaces of saidfirst and second base members.
 4. A cable splice closure according toclaim 3, wherein:said first and second base members are interconnected,said tubular cover means is arranged to be applied axially from an endof said interconnected base members, and said peripheral surfaces ofsaid base members taper towards said end of said interconnected basemembers from which said tubular cover means is applied.
 5. A cablesplice closure according to claim 1, wherein:an outer edge of saidtubular cover means is formed with a mounting projection for mountingsaid cable splice closure to a support rail.
 6. A cable splice closureaccording to claim 1, wherein:wherein said cable splice closure isarranged so that said O-ring is rolled more than 60%, but less than 90%,of said peripheral length of said O-ring.
 7. A cable splice closureaccording to claim 1, wherein:wherein said cable splice closure isarranged so that said O-ring is rolled approximately 75% of saidperipheral length of said O-ring.